Soft Robotic Finger with Variable Effective Length enabled by an Antagonistic Constraint Mechanism
This work addresses the problem of enhancing grasping adaptability for irregular objects in soft robotics, offering a simpler and faster alternative to existing VEL methods, though it appears incremental as it builds on prior VEL research.
The paper tackled the challenge of achieving variable effective length (VEL) in soft robotic grippers without complex pneumatic circuits or slow phase-changing materials by proposing a fold-based soft actuator made from 3D printed NinjaFlex and an antagonistic constraint mechanism, resulting in improved conformity and grasping performance as demonstrated in experiments.
Compared to traditional rigid robotics, soft robotics has attracted increasing attention due to its advantages as compliance, safety, and low cost. As an essential part of soft robotics, the soft robotic gripper also shows its superior while grasping the objects with irregular shapes. Recent research has been conducted to improve its grasping performance by adjusting the variable effective length (VEL). However, the VEL achieved by multi-chamber design or tunable stiffness shape memory material requires complex pneumatic circuit design or a time-consuming phase-changing process. This work proposes a fold-based soft robotic actuator made from 3D printed filament, NinjaFlex. It is experimentally tested and represented by the hyperelastic model. Mathematic and finite element modelling is conducted to study the bending behaviour of the proposed soft actuator. Besides, an antagonistic constraint mechanism is proposed to achieve the VEL, and the experiments demonstrate that better conformity is achieved. Finally, a two-mode gripper is designed and evaluated to demonstrate the advances of VEL on grasping performance.